1. Field of the Invention
The present invention relates to the field of electronic connectors. More particularly, the present invention relates to dual-in-line Universal Serial Bus ("USB") connector.
2. Description of Art Related to the Invention
For many years, personal computers ("PCs") have been designed with one or more circuit boards which are electrically coupled together in order to perform various operations. One of these circuit boards, namely the "motherboard", utilizes connectors to enable input/output ("I/O") peripherals to communicate with primary electronic components of the computer such as, for example, its processor(s), "I/O" controller and the like. As shown in FIG. 1, a PC 1 includes a number of connectors accessible from a backside of its chassis 10. These connectors include (i) a pair of audio plugs 20 and 25 which allow audio to be input from a transmitting source (e.g., a microphone) and output to a receiving source (e.g. speakers), (ii) a keyboard connector 30, (iii) a mouse connector 40, (iv) a display connector 50, (v) a parallel port connector 60 enabling one or more data bits to be communicated to or from the PC 1 and (vi) a pair of serial communication (COM) port connectors 70 and 75, individually referred to as a "COM1 port connector" and a "COM2 port connector". In general, each of these COM port connectors is a standard 9-pin D-Sub connector which is well-known in the art.
Recently, the computer industry has made significant efforts to develop a "plug and play" environment for PCs which have lead to the development of two types of Universal Serial Bus ("USB") connectors; namely, a standard USB connector as shown in FIGS. 2a-2b and a "stacked" USB connector as shown in FIGS. 3a-3b. These USB connectors offer a number of advantages. One advantage is that, unlike COM port connectors, USB connectors employ a two signal differential communication scheme which allows more than one USB peripheral to be connected to a single USB port. Another advantage associated with the differential communication scheme is that it provides a data link capable of operating at a faster transmission rate than conventional serial links.
Referring now to FIG. 2a, the standard USB connector 100 comprises a USB port 105 sized to receive a USB adapter 110 of a USB-compatible peripheral in order to establish an electrical connection with that USB-compatible peripheral. The USB connector 100 further comprises (i) a pair of mounting tabs 115 and 120 which are soldered to a motherboard 125 in order to establish a strong connection thereto and (ii) four signal pins 130a-130d having the following pin definitions in compliance with Universal Serial Bus Specification Revision 0.99.
______________________________________ PIN No. DESCRIPTION ______________________________________ Pin 1 (130a) V.sub.cc Pin 2 (130b) -DATA Pin 3 (130c) +DATA Pin 4 (130d) GND ______________________________________
As shown in FIG. 2b, in the event that the standard USB connector 100 is a throughhole connector requiring holes to be precut into the motherboard 125 to accommodate the mounting tabs 115 and 120 and signal pins 130a-130d, a typical board layout footprint required for the standard USB connector of FIG. 2a is shown. The footprint includes a pair of mounting holes 135 and 140, which are sized and spaced to accommodate the mounting tabs 115 and 120, and four signal pin holes 145a-145d arranged so that the signal pins 130a-130d of FIG. 2a are inserted therethrough once the mounting tabs 115 and 120 are soldered at the mounting holes 135 and 140. Since the signal pins 130a-130d are not separated by a uniform distance, namely the first and second pins 130a and 130b as well as the third and fourth pins 130c and 130d are separated by approximately 0.10 inches while the second and third pins 130b and 130c are separated by approximately 0.08 inches, a customized, costly 1.times.4 stake pin connector would be required to cable the USB connections to another location on the motherboard 125.
Referring to FIG. 3a, the stacked USB connector 200 provides a first USB port 205 and a second USB port 210 for two USB adapter plugs. The USB ports 205 and 210 are arranged vertically to minimize the amount of board space needed on the motherboard 125. The stacked USB connector 200 includes four mounting tabs 215, 220, 225 and 230 which, are soldered to the motherboard 125 like the standard USB connector of FIG. 2a. The stacked USB connector 200 further includes eight (8) signal pins 235a-235h which are horizontally aligned in two four-pin groups such that pins 235a-235d provide connections for the first USB port 205 and pins 235e-235h provide connections for the second USB port 210. The signal pins 235a-235h comply with the USB Specification Revision 0.99 for each port of the stacked USB connector and are defined as follows:
______________________________________ PIN No. DESCRIPTION ______________________________________ Pin 1 (235a) V.sub.cc for USB Port 1 Pin 2 (235b) -DATA for USB Port 1 Pin 3 (235c) +DATA for USB Port 1 Pin 4 (235d) GND for USB Port 1 Pin 5 (235e) V.sub.cc for USB Port 2 Pin 6 (235f) -DATA for USB Port 2 Pin 7 (235g) +DATA for USB Port 2 Pin 8 (235h) GND for USB Port 2 ______________________________________
As shown in FIG. 3b, in the event that the stacked USB connector 200 is a throughhole connector requiring holes to be precut into the motherboard 125 to accommodate the mounting tabs 215, 220, 225 and 230 and signal pins 235a-235h, a typical board layout footprint required for the stacked USB connector 200 of FIG. 3a is shown. The footprint includes four mounting holes 250, 255, 260 and 265, which are sized and spaced to accommodate the mounting tabs 215, 220, 225 and 230, respectively. The footprint further includes eight (8) signal pin holes 270a-270h arranged in two, four-hole groupings 275 and 280 in a manner similar to the signal pin holes 145a-145d of the standard USB connector of FIG. 2b but instead having two aligned groupings 275 and 280 instead of just one grouping.
These conventional USB connectors have a number of disadvantages. For example, certain low-profile motherboards require their components to be shorter a maximum height to guarantee that a sufficient distance is maintained between the inner walls of the chassis of the PC and the motherboard. Thus, in some situations, stacked USB connectors may not be used. Although it is contemplated that the standard USB connector may be used as the alternative, it does not provide dual USB ports which can, among other things, be used to initially support two USB-compatible peripherals. Furthermore, two standard USB connectors placed side-by-side could not be used to provide dual USB ports because the collective width of the two standard USB connectors exceeds the board width allocated to the COM port connector.
It is desirable to develop and configure a new type of USB connector as an alternative to one of two COM port connectors (i.e., support an optional configuration of one COM port connector and a dual-in-line USB connector instead of two COM port connectors) for two primary reasons. One reason is that the elimination of a COM port connector still provides support for serial communication through the other COM port connector. The second reason is that many countries around the World rely heavily on the availability of two COM port connectors and may not initially accept USB technology. This allows motherboard manufacturers an ability to produce a single motherboard that is capable of supporting either USB and dual COM options.
Therefore it would be advantageous to develop a dual in-line USB connector, compatible with low-profile motherboards, that would comply with the board width constraints associated with the COM port connector as well as utilize the same mounting holes used by the COM port connector. It would be also advantageous to develop the dual-in-line connector with signal pins separated by a uniform distance so that standard stake pin connectors, instead of custom stake pin connectors, can be used to cable one or both of the USB connections to another location on the motherboard.